Control unit



F. KILLAIRE CONTROL UNIT May 25, 1943.

Filed Feb. 24, 1941 tip FIG. 2.

Ill/SUM 7707 FIG.4.

INVENTOR. KIL'LAI RE FREDERICK Patented May 25, 1943 UNITED STATES PATENT OFFICE CONTROL UNIT Application February 24, 1941, Serial N 0. 389,406

Claims.

The invention relates to control units and reiers more particularly to electrical progressive control units for pilot circuits only.

The invention has for one of its objects to provide a compact construction of control unit which is relatively small and of relatively light weight.

The invention has for another object to provide a progressive control unit so constructed that resistances which can be noticed by the operator are interposed to the relative movement of the parts to successively close the electrical circuits.

The invention has for further objects to provide an improved construction of push button and to provide an improved safety device for controlling the operation of a pair of associated push buttons.

With these as well as other objects in view, the invention resides in the novel features of construction and combinations and arrangements of parts as more fully hereinafter set forth.

In the drawing:

Figure l is a perspective View of a control unit embodyin the invention;

Figure 2 is a vertical section through the axes of the push buttons;

Figure 3 is a vertical section at right angles to Figure 2 and through the axis of one of the push buttons;

Figure 4 is a developed elevation showing the positions of the contact members carried by a body of one of the push buttons.

While the control unit may have various uses, it is particularly applicable to cranes and hoists to control the operation of their electric motors. More specifically, the control unit is an electrical progressive control unit for pilot circuits only which upon being closed operate magnetic switches in the electric motor circuits.

While the control unit is adapted to control the operation of one electric motor, or a plurality of electric motors, it is illustrated as adapted to control the operation of a single electric motor. The control unit comprises the casing I and the two push button switches 2 and 3, which latter would be duplicated for each extra electric motor to be included. The casing is formed of the bottom and top sections 4 and 5, respectively, the former having the base 8 with the integral upstanding side flanges 7 and the integral upstanding ends 8. The top section has the top 9 and the integral downwardly extending sides I l] with integral inturned flanges H at the ends of the top and sides. The top section is adapted to embrace the bottom section with the sides it] overlapping the flanges l and the inturned flanges I l overlapping the ends 8. The top section is adapted to be secured to the bottom section by the screws [2 which extend through the top t and are threaded into the ears i3 formed on the ends 8. To provide access to the push button switches, the top 9 is formed with two openings registering with the caps or push buttons of the push button switches and two upstanding collars i l are secured to the edges of the openings.

The two push button switches are alike, each comprising the insulator body it: carrying the contact members it, the contact member l'l movable into engagement with the contact members It, and the insulator cap or push button 2tupon the contact member ti.

Each insulator body i5 is secured at its inner or lower end to the base E by suitable means, such as the screws is. As shown, each insulator body is hexagonal and has the central longitudinally extending cylindrical recess 2%? leading from its outer or upper end to near its inner or lower end. Threaded into each side of the insulator body is a retainer 2! having a polygonal head 22 outside the insulator body for engagement by a suitable wrench. The retainer extends to the recess 20 and is hollow to receive a con act member I 5 and a coil spring 23' for urging the contact member toward the recess to normally project inwardly beyond the wall of the recess. The contact member It is preferably a steel ball held from disengagement from the retainer by turning in its inner end to a diameter smaller than the ball. The retainer is preferably formed of brass and has the screw 2 threaded therein for clamping a wire to the retainer.

The contact member ii is a hollow cylindrical plunger preferably formed of steel and slidable within the recess 28. An insulator cap or push button 25 is threaded on the outer or upper end of the plunger and a coil spring 2t encircling the plunger and abutting the insulator body i5 and the annular shoulder 23 in the cap or push button normally holds the plunger in its outermost or fully raised position, at which time it preferably clears all the contact members it. The fully raised position is controlled by the retaining screw 28 threaded into the bottom of the recess 20 and extending through the inner or lower end of the plunger and having a head 29 within' the plunger and adapted to abut its inner or lower end.

Inasmuch as the progressive control unit is for pilot circuits only, which require but very little current ordinarily not in excess of two or three ball contacts for each push buttton switch providing five electric circuits in each of which the outermost or uppermost ball contact forms a part. As shown particularly in Figure 4, the six ball contacts are longitudinally and angularly spaced of the insulator body and arranged in an upper and a lower series of three ball contacts each with the ball contacts of either series angularly spaced with respect to the ball contacts of the other series. With this arrangement electrical clearance with minimum stroke of the reciprocable contact member and a relatively large number of ball contacts is obtained. It is to be noted that one push button switch controls the electric current for driving the electric motor in one direction, while the other push button switch controls the electric current for driving the electric motor in the reverse direction.

30 is a safety device for the control unit comprising the bar 3| which is secured at its ends to the insulator bodies of the push button switches and the bar 32 which is pivotally mounted at its middle upon the middle of the bar 3! in a zone above the insulator bodies. The bar 32 has the transverse end portions 33 which are adapted to be abutted by the insulator caps 25 when moved inwardly or lowered. The construction of the safety device is such that if one of the reciprocable plunger contact members is moved inwardly or lowered and sticks it will be positively moved outwardly or raised when the other reciprocable plunger contact member is moved inwardly or lowered.

The construction is such that the control unit is relatively small and of relatively light weight so that when suspended from a crane or hoist, for example, by a cable 'it may be readily grasped and operated by one hand of the operator permitting the operator to use his other hand in guiding the work. The construction is also such that the operator can readily feel the progressive making of the pilot circuits.

What I claim as my invention is:

1. In a progressive control unit, an insulator body having a recess, contact members carried by said body and extending into the recess at difierent zones longitudinally and angularly of the recess, a hollow plunger contact member movable longitudinally within the recess progressively into engagement with said first mentioned contact members, said plunger contact member having a transverse Wall at its lower end, an insulator cap upon the outer end of said plunger contact member, a coil spring encircling said plunger contact member and abuttingsaid body and cap for normally urging said plunger contact member to its outermost position, and a retaining screw threaded into the bottom of the recess and having a head extending within said plunger contact member for limiting the outward movement of said plunger contact member.

2. In a progressive control unit, a plurality of insulator bodies having substantially parallel recesses, contact members carried by each of said bodies extending into the recesses at difierent zones longitudinally and angularly of the recesses, contact members movable longitudinally within the recesses in an inward direction to successively engage said first mentioned contact members, insulator caps at the outer ends of said longitudinally movable contact members, a bar extending between said insulator bodies and secured thereto, and a, safety member pivotally mounted on said bar and having portions engageable with said caps to thereby cause movement of one of said longitudinally movable contact members in an outward direction when the other of said longitudinally movable contact members is moved in an inward direction.

3. In a progressive control unit, a body having a recess, contact members carried by said body in insulated relation'to each other and extending into the recess at difierent zones longitudinally and angularly of the recess, a hollow plunger contact member movable longitudinally within the recess progressively into engagement with said first mentioned contact members, said plunger contact member having a transverse shoulder at its inner side, an insulator cap upon the outer end of said plunger contact member, a coil spring encircling said plunger contact member and abutting said body and cap for normally urging said plunger contact member to its outermost position, and a retaining member secured to said body and having a shouldered portion extending within said plunger contact member and engageable with said transverse shoulder for limiting the outward movement of said plunger contact member.

4. In a progressive control unit, a body having a recess, an electrical conducting member movable longitudinally within the recess, contact members carried in insulated relation to each other by said body, said contact members being spaced longitudinally and angularly of said body and extending into the recess for progressive engagementrby said electrical conducting member, said contact members being arranged in a pair of series occupying different zones longitudinally of said body with the contact members of one series between the contact members of the other series angularly of said body.

. 5. In a progressive control unit, telescoping members relatively movable longitudinally of each other, one of said telescoping members forming an electrical conductor, contact members carried in insulated relation to each other by the other of said telescoping members, said contact members being spaced longitudinally and angularly of said last mentioned telescoping member for FREDERICK KILLAIRE. 

